Obtaining electrical energy from renewable sources is increasingly gaining importance. One source of renewable energy is sunlight, convertable into a DC voltage by means of photovoltaic generators (PV generators). For this purpose, a plurality of solar modules are connected in series to form so called strings that can, if appropriate, also be further connected in parallel with further strings. Here, the length of the strings determines the achievable DC voltage.
Particularly in the case of power generation plants having powers that nowadays exceed a megawatt, it is desirable to operate with high generator voltages, corresponding to large string lengths, in order to keep the currents flowing low. This reduces the outlay on connections within the plant by virtue of relatively small line cross sections. At the same time, it is desirable to select a generator voltage so that the peak values of the line voltage are exceeded.
Since a frequent requirement exists within the power generation plant to adjust the value of the generator voltage before feeding into the connected power grid, in particular to step up the generator voltage to a voltage value of an intermediate circuit, the plants frequently have a configuration in which a step-up converter, an intermediate circuit and a converter bridge are connected in series. The losses of the individual components add up in such a configuration.